We have investigated the alignment properties of liquid crystals induced by
multiple rubbing of the surfaces in different directions. Experiments were
carried out using homeotropic and hybrid-aligned samples. It is experiment
ally found that the alignment of the liquid crystals is along neither of th
e rubbing directions, but instead lies along an axis intermediate between t
hese two directions, and that the direction depended on the relative streng
th of rubbing along the two axes. A model that assumed the grooves along tw
o rubbing directions is proposed, and the relation between the orientation
of the liquid crystal and the relative rubbing strength is analyzed. We fou
nd that this model can explain the observed experimental results. (C) 2000
American Institute of Physics. [S0003-6951(00)02330-5].